The contact-type transducer recording heads used to read and write data in backup drives of computers can become dirty with use. The accumulation of contaminants such as dust, debris, etc., on the heads can interfere with their normal operations, which can in turn lead to errors in the reading and the writing of the data from and to the magnetic tape. In addition, the magnetic recording tape engages the recording head under tension, leading to the erosion of the magnetic oxide particles forming the recording media from the recording tape and the subsequent emplacement of those eroded particles upon the head. These and other known sources of contamination make periodic cleaning of the head necessary if the head is to continue to operate properly. Proper cleaning is important since a dirty head- whether due to no cleaning at all or an ineffective cleaning-may result in a loss of data whose value is often inestimable.
Known head cleaning devices for magnetic recording heads include those disclosed in U.S. Pat. No. 3,789,452 to Nemoto; U.S. Pat. No. 4,408,241 to Ogawa; U.S. Pat. No. 4,751,600 to Cecil et al.; U.S. Pat. No. 4,755,910 to Rudi; U.S. Pat. No. 5,012,377 to Siddio; and Japanese Patent Nos. 60-10411, 60-170017, 2-35618, and 3-173912. The Nemoto and Ogawa patents appear to be directed principally to audio tape players, while the majority of the remainder of the aforementioned patents appear to be directed to cleaning read/write heads associated with computer hardware. Japanese 60-170017 and, in part, Siddio, appear to be directed to video applications.
The Cecil and Rudi patents disclose a head cleaner that comprises a sponge that is held in a cassette similar in size to that used to hold the magnetic tape. A cleaning solution is applied to the sponge which is reciprocated up and down upon the surface of the head by means of a crankshaft-type of mechanism driven by the capstan of the computer backup tape drive. Thus, to use the Cecil or Rudi cleaner, cleaning solution must be applied by hand to the sponge, after which the cassette is inserted into the tape drive for the cleaning process. Cleaning continues until the cleaning cassette is removed from the tape drive.
While potentially valuable as a head cleaning aid, the Cecil/Rudi types of cleaning devices suffer from several well recognized deficiencies. For example, the length of time that the cassette is in the backup drive cleaning the head is determined solely by the end user or customer. The ability of anyone--manufacturer or customer--to control the quality of the cleaning of a single unit let alone an entire product line in a consistent manner is minimal as a result. In addition, because these kinds of cleaning devices wipe generally the same area of sponge over the head repeatedly as the sponge is moved up and down over the surface of the head, the contaminants whose removal is desired may instead be smeared out over the head and only partially removed. Yet another shortcoming in the ability to control the quality of cleaning that these types of cleaners provide is that they each rely upon the placement of a specific amount of cleaning solution on the sponge. Putting too little solution on the sponge may result in an ineffective cleaning. If too much solution is placed on the sponge, however, the excess cleaning solution may be squeezed out of it when the sponge is placed into contact with the head, thereby causing the cleaning solution to drip off the sponge into the interior of the tape drive and creating the potential for damaging the tape drive or other electronic equipment associated therewith.
A final deficiency of the Cecil/Rudi type of device is that, with presently available equipment, the need for the addition of the cleaning solution to the sponge means that human intervention is required in what could otherwise be an automated process. Thus, this deficiency is a particular hinderance to the use of these types of wet cleaning devices in data library systems where robotic arms are otherwise used to manipulate the data cassettes and to insert and remove them from tape drives. This need to add the solution to the sponge by hand therefore, prevents the cleaning process from being performed by robotics according to a pre-established cleaning schedule.
Dry cleaning techniques, rather than the aforementioned wet cleaning techniques are also known. Thus, as shown in Nemoto, which as noted is directed to an audio application, a dry cleaning tape formed of a woven material is used to remove contaminants from a read/record head of an audio player. The cassette is inserted into the audio tape drive and the takeup reel is driven directly by the drive of the audio unit. In this type of cleaning cassette, the contaminants are caught by the interstitial gaps that exist between the threads in the weave of the cleaning tape. While effective in this particular application, such cleaning devices have been generally considered ineffective for use in a computer tape backup drive system because the drive speed of the cleaning tape past the read/write head generally lies between ninety (90) and one hundred twenty (120) inches per second (ips), the normal range of operational speed of such tape drives when reading or writing data. This speed is too great to clean the head of a computer backup tape drive effectively. Additionally, because these types of dry cleaning tapes can be generally rewound, they can be reused over and over again, thus eliminating any ability of the manufacturer of the cleaning tape to control the quality and effectiveness of the cleaning process. Again, this feature of this type of cleaning device makes it undesirable for use in the computer tape drive backup system application where suitable cleaning is essential for a properly operating recording head.
It would be desirable to have a new and improved head cleaning device that utilizes dry cleaning rather than wet cleaning techniques to remove contaminants from a read/write head; that cooperates with a tape drive to indicate that a cleaning media rather than a data media has been inserted into the tape drive; that does not rely upon cleaning the head with an already used cleaning surface; that does not rely upon the customer to unwittingly use the cleaning device a proper length of time; and that cannot be reused when the supply of cleaning tape has been used once.